A 14-year-old boy has died after crashing his bicycle at Stromlo Forest Park on Saturday afternoon.

He was treated at the scene before being taken to hospital with life-threatening injuries, where he later died.

The area is being considered a road-related area as Stromlo Forest Park is open to the public and designated for use by cyclists. This brings the ACT road toll for this year to eight.

Anyone who witnessed the incident is urged to contact police via the Crime Stoppers ACT website.